In 1967, Military Assistance Command Vietnam Studies and Observations Group (MAC V SOG), OPS-35 (Ground Reconnaissance) Program was expanded. With the additional personnel, MAC V SOG’s House 50 (Supply Office / S4) requested the Counter Insurgency Support Office (CISO) to procure additional SOG knives.
Conrad “Ben” Baker redesigned the knife with a larger cross guard and more refined blade. With the loss of the first batch of Fat Guard SOG knives during the logistic process he also requested the knives be individually numbered on the ricasso that start at 1 and continue through 3700. The initial batch of knives had variations in the tempering process from an almost parkerized black, to blued, and other versions of a plum color. The number system started out as hand stamped and the ladder were acid etched. I have encountered two different stylized versions of the acid edge design.